Two independent real-time precursors of the 7.8 Mw earthquake in Ecuador based on radioactive and geodetic processes—Powerful tools for an early warning system

Toulkeridis, Theofilos; Porras, Luis Fernando Barón; Tierra, Alfonso; Toulkeridis-Estrella, Katerina; Cisneros, David A.; Luna, Marco P.; Carrión, José; Herrera, Myrian; Murillo, Alfonso Renato Vargas; Salinas, Juan Carlos Perez; Tapia, S.; Fuertes, Walter; Salazar, Rodolfo

doi:10.1016/j.jog.2019.03.003

Cited by 30 publications

(10 citation statements)

References 61 publications

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“…Based on VTEC data, He and Heki (2017) identified anomalous signal almost immediately (∼17 min) before the onset of the earthquake through the use of the reference curve method, and Carlos Sotomayor-Beltran (2019) observed a negative ionospheric anomaly 10 days before the incident by using a statistical method [38], [39]. An unusual increase in the environmental radiation level a few hours before the earthquake highlights the importance of the precursor role of environmental radiation in the precise location of earthquakes in Ecuador [40], [41]. Twenty-four GPS stations distributed throughout Ecuador recorded significant changes in their usual locations a few minutes before the earthquake, which can be used for forecasting in the medium and short terms along active continental margins [41].…”

Section: Introductionmentioning

confidence: 99%

“…An unusual increase in the environmental radiation level a few hours before the earthquake highlights the importance of the precursor role of environmental radiation in the precise location of earthquakes in Ecuador [40], [41]. Twenty-four GPS stations distributed throughout Ecuador recorded significant changes in their usual locations a few minutes before the earthquake, which can be used for forecasting in the medium and short terms along active continental margins [41].…”

Section: Introductionmentioning

confidence: 99%

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Precursor Analysis Associated With the Ecuador Earthquake Using Swarm A and C Satellite Magnetic Data Based on PCA

Zhu

Fan

et al. 2019

IEEE Access

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In this paper, we revisit this earthquake by simultaneously analyzing the magnetic field data of Swarm satellite A and satellite C based on principal component analysis (PCA), and the eigenvalues and principal components are calculated throughout 2016. We find that the first principal component mainly contains the signal originating from solar-terrestrial effects such as geomagnetic activity since the first eigenvalue and the geomagnetic index are highly correlated. Therefore, the second principal component is used to extract the anomalies associated with the Ecuador earthquake in terms of skewness and kurtosis. The anomalous tracks of the S-K (Skewness-Kurtosis) coefficient are accumulated from 90 days before the event to 30 days after. The cumulative number follows an accelerating power-law behavior before the earthquake and decelerating recovery behavior after the earthquake; moreover, the inflection point of the sigmoidal fitting curve is close to the time of the earthquake. The cumulative number of anomalous tracks in the random regions shows a linear increase, further verifying the correlation between anomalies extracted and the Ecuador earthquake. This phenomenon could be related to the preparation phase and the aftershock phase of the Ecuador earthquake.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Precursor Analysis Associated With the Ecuador Earthquake Using Swarm A and C Satellite Magnetic Data Based on PCA

Zhu

Fan

et al. 2019

IEEE Access

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“…These economic struggles have compromised occasionally the government's GDP leading to social unrest and manifestations (Toulkeridis et al, 2019;Hochstetler, 2006;Lucero, 2001;Korovkin, 2000;Kennemore and Weeks, 2011).…”

Section: The Importance Of the Impact Of A Meteor To Ecuadormentioning

confidence: 99%

Shock Metamorphism in Volcanic Rock Due to the Impact of the Miguir-Cajas Meteorite in 1995 and Its Importance for Ecuador

Toulkeridis¹,

Echegaray-Aveiga²,

MARTINEZ-MALDONADO³

2021

GTG

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In the past of the earth several asteroids and meteoroids have been impacted, but most of these collisions have been eroded and today there are only sometimes direct and indirect indications, such as massive extinctions of species in the form of fossils, layers with content of extraterrestrial material among others. Based on our recent reconnaissance in the field in 2017, we have been able to identify a new impact of a meteorite on volcanic rock of the Miocene Tarqui Formation in central Ecuador. We were able to reveal and reconstruct the corresponding trajectory as well as its impact day being in 1995. Based on known impacts in South America, this is the very first to have been impacted on rocks, which would lead to a clear shock metamorphism. This discovery of the impact on a rock may soon be a major tourist attraction of the country due to its accessibility and importance for being unique in Ecuador and on the continent.

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“…The poor quality of the soils due to their young age produces unfavorable conditions that correspond to the Holocene [1][2][3][4][5][6][7][8][9][10][11][12]. Historically, older buildings in alluvial valleys filled with Quaternary deposits are the most vulnerable, as was documented in past earthquakes in the province of Manabí, in the central coastal area of Ecuador (Figure 1) [11,[13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Some specialists have evaluated the surface coseismic effects related to liquefaction, exposing their criteria in a variety of studies [30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45]…”

Section: Introductionmentioning

confidence: 99%

Assessing Susceptibility to Soil Liquefaction Using the Standard Penetration Test (SPT)—A Case Study from the City of Portoviejo, Coastal Ecuador

Ortiz-Hernández

Chunga

Pastor

et al. 2022

Land

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The city of Portoviejo in coastal Ecuador was severely affected during the 16 April 2016, Pedernales earthquake (Mw 7.8). Various coseismic liquefaction phenomena occurred, inducing lateral spreading, sand boils, ground subsidence, and sinkholes in soils with poor geotechnical quality in the alluvial and alluvial–colluvial sedimentary environment. Therefore, the main aim of this study was to collect data from standard penetration tests (SPT) and shear velocity and exploratory trenches and to calculate the liquefaction potential index (LPI) by considering a corresponding seismic hazard scenario with an amax = 0.5 g. From these data, a liquefaction hazard map was constructed for the city of Portoviejo, wherein an Fs of 1.169 was obtained. It was determined that strata at a depth of between 8 and 12 m are potentially liquefiable. Our quantitative results demonstrate that the city of Portoviejo’s urban area has a high probability of liquefaction, whereas the area to the southeast of the city is less sensitive to liquefaction phenomena, due to the presence of older sediments. Our results are in accordance with the environmental effects reported in the aftermath of the 2016 earthquake.

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Two independent real-time precursors of the 7.8 Mw earthquake in Ecuador based on radioactive and geodetic processes—Powerful tools for an early warning system

Cited by 30 publications

References 61 publications

Precursor Analysis Associated With the Ecuador Earthquake Using Swarm A and C Satellite Magnetic Data Based on PCA

Precursor Analysis Associated With the Ecuador Earthquake Using Swarm A and C Satellite Magnetic Data Based on PCA

Shock Metamorphism in Volcanic Rock Due to the Impact of the Miguir-Cajas Meteorite in 1995 and Its Importance for Ecuador

Assessing Susceptibility to Soil Liquefaction Using the Standard Penetration Test (SPT)—A Case Study from the City of Portoviejo, Coastal Ecuador

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